“There is only nobility of birth, only nobility of blood. When one speaks of "aristocrats of the spirit," reasons are usually not lacking for concealing something. As is well known, it is a favorite term among ambitious Jews. For spirit alone does not make noble. Rather, there must be something to ennoble the spirit. What then is required? Blood.”

Nelly Dean on Hareton (Ch. XXXIII).
Wuthering Heights (1847)

Source: Hunted

Source: Drenai series, Quest for Lost Heroes, Ch. 3

Source: The Duke's Children (1879), Ch. 61
Context: But between you and me there should be no mention of law as the guide of conduct. Speak to me of honour, of duty, and of nobility; and tell me what they require of you.

(Love, Art, and Culture, p. 24).
Book Sources, The Wisdom of W.E.B. Du Bois (2003)

Sādhanā : The Realisation of Life http://www.spiritualbee.com/spiritual-book-by-tagore/ (1916)
Context: Of course man is useful to man, because his body is a marvellous machine and his mind an organ of wonderful efficiency. But he is a spirit as well, and this spirit is truly known only by love. When we define a man by the market value of the service we can expect of him, we know him imperfectly. With this limited knowledge of him it becomes easy for us to be unjust to him and to entertain feelings of triumphant self-congratulation when, on account of some cruel advantage on our side, we can get out of him much more than we have paid for. But when we know him as a spirit we know him as our own. We at once feel that cruelty to him is cruelty to ourselves, to make him small is stealing from our own humanity...

cnn.com http://edition.cnn.com/2007/US/04/03/collins.commentary/

An introduction to this book
The Religion of God (2000)

Source: Guards! Guards!